title: A randomized, prospective, double-blind trial comparing 3% chloroprocaine followed by 0.5% bupivacaine to 2% lidocaine followed by 0.5% bupivacaine for interscalene brachial plexus block.
abstract: BACKGROUND
  The combination of 2-chloroprocaine and bupivacaine (C/B) for regional anesthesia has been described, but its use was largely abandoned due to equivocal results in efficacy. In this prospective, double-blind, randomized study, we compared the onset of an interscalene block using C/B versus a combination of lidocaine and bupivacaine (L/B).
  
  
  METHODS
  Thirty patients scheduled for shoulder arthroscopy under interscalene block were divided into two groups of 15 each. One group (C/B) received 3% 2-chloroprocaine combined with bicarbonate and epinephrine, immediately followed by 0.5% bupivacaine and epinephrine, whereas the other group (L/B) received 2% lidocaine instead of 3% 2-chloroprocaine. Motor and sensory block were assessed every 15 s. The primary end-point was the time of onset to complete motor block. Time-to-event (survival) statistical analysis tests were applied.
  
  
  RESULTS
  One L/B patient had a failed block, and was excluded. The median time to motor block for C/B and L/B was 90 (15-575) and 180 (15-3720) s, respectively (P = 0.0325), and to sensory block for C/B and L/B was 90 (30-600) and 210 (30-3900) s, respectively (P = 0.0185). Survival analysis showed that in 5 min, 13 of 15 patients from the C/B group but only 7 of 14 from the L/B group had a successful motor block. In 10 min, 15 of 15 patients from the C/B group but only 10 of 14 from the L/B group had a successful motor block. It took as long as 60 min to assess block success/failure for blocks in the L/B group.
  
  
  CONCLUSIONS
  This study demonstrates that a successful block was more rapid using C/B than L/B for interscalene blocks.
authors.affiliation: Department of Anesthesiology, New York Methodist Hospital, 506 Sixth St., Brooklyn, NY 11215, USA. s1jafari@aol.com
authors.forename: Soheila
authors.initials: S
authors.lastname: Jafari
authors.forename: Allison I
authors.initials: AI
authors.lastname: Kalstein
authors.forename: Habib M
authors.initials: HM
authors.lastname: Nasrullah
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Hedayatnia
authors.forename: Joel M
authors.initials: JM
authors.lastname: Yarmush
authors.forename: Joseph
authors.initials: J
authors.lastname: SchianodiCola
mesh_terms: D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000627:therapeutic use*; D001182:Arthroscopy; D001917:Brachial Plexus / Q000187:drug effects / Q000502:physiology*; D002045:Bupivacaine / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000187:drug effects; D009407:Nerve Block / Q000379:methods*; D011343:Procaine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D011446:Prospective Studies; D012677:Sensation / Q000187:drug effects; D012785:Shoulder Joint / Q000601:surgery
chemical_list: D000779:Anesthetics, Local; D011343:Procaine; C004616:chloroprocaine; D008012:Lidocaine; D002045:Bupivacaine